Characteristics of MHC antigen expression and tumor-infiltrating mononuclear cells in renal cell adenomas and carcinomas

Abstract

We compared the expression of major histocompatibility complex (MHC; HLA class 1 and 11) antigens and the presence of tumor-infiltrating mononuclear cells presenting S 100 protein (S 100), CD68 antigen, or CD45RO antigen in formalin-fixed, paraffin-embedded tissue sections of 10 renal cell carcinomas and 9 renal cell adenomas using immunohistochemistry. The expression of B2-microglobulin (B2MG) as an HLA class 1 antigen in al1 10 cases (100%) and that of HLA-DR/a as an HLA class 11 antigen in 7 of 10 cases (70%) of carcinoma was stronger than that in the adjacent proximal convoluted tubule, but was respectively not different to weaker in 8 of 9 cases and not different to markedly weaker in al1 cases of adenoma. Furthermore, there was comparatively dense infiltration by S 100(+) antigen-presenting cells in the carcinomas, but almost none in the adenomas and generally dense infiltration by CD45RO(+) T cells and CD68(+) macrophages in the carcinomas, but little to none in the adenomas. We concluded that the generaily enhanced expression of MHC antigens in carcinomas must be an immunophenotypic deviation from not only the adjacent proximal convoluted tubule but also adenomas, and that the predominant infiltration of antigen-presenting cells, T cells and macrophages in the carcinomas, but not in the adenomas, reflects the anticancer immune reaction